1. Technical Fields
This invention relates generally to thermal-transfer type printers that use ink sheet mechanisms to print with ink on plain paper versus using heat alone on thermally sensitive paper. In particular, it relates to printers that are able to rejuvenate ink sheets using a form of powder ink.
2. Description of the Prior Art
Thermal transfer imaging devices are generally very compact and highly reliable devices, which have been typically used in facsimile (FAX) machines. More widespread use has been prohibited by high operating costs. Such high costs stem mainly from ink sheets that can only be used once. There has been a long felt need to develop an ink sheet that can be used over and over. A number of methods have thus far been devised to regenerate, or rejuvenate, ink sheets within printers for their immediate re-use.
A direct ink layer rejuvenation system has long been proposed for rejuvenating the ink layer on ink sheets with components that have been used for thermal transfer. Such a system melts ink with a heat element and then supplies the melted ink for ink sheet rejuvenation. Rejuvenation methods that use powder ink are described in U.S. Pat. No. 4,467,332. A conductive powder ink has been used as a method that solves certain problems connected with ink sheet rejuvenation technology. For example, the printer described in laid open Japanese patent application number 63-36114 used powder ink.
The print quality available with prior art ink sheet rejuvenation technologies has been of widespread, and much debated concern. Absent from the prior art are techniques to avoid areas on rejuvenated ink sheets that probably contain defects, and there are no solutions to contamination caused by loose powder ink floating around within the ink sheet printing mechanism.